Self configuring voltage regulators

ABSTRACT

Some of the embodiments of the present invention provide a voltage regulator comprising a first driver, a second driver, and a controller configured to control the first driver and the second driver to selectably operate in one of a plurality of operating modes, including an external driver mode and an internal driver mode, wherein which one of the plurality of operating modes is selected is based on presence or absence of one or more external drivers. Other embodiments are also described and claimed.

CROSS REFERENCE TO RELATED APPLICATIONS

The present application claims priority to U.S. Patent Application No.61/014,114 filed Dec. 17, 2007, entitled “SELF CONFIGURING VOLTAGEREGULATOR,” the entire specification of which is hereby incorporated byreference in its entirety for all purposes, except for those sections,if any, that are inconsistent with this specification.

TECHNICAL FIELD

Embodiments of the present invention relate to the field of voltageregulators, and more particularly, to self configuring voltageregulators.

BACKGROUND

All electronic circuits need a well regulated power supply to ensureproper operation of the circuit, which may be supplied by one or morevoltage regulators. It may be possible to integrate a voltage regulatorinto an integrated circuit (IC) chip. It may also be possible tointegrate a voltage regulator to other components of an integratedcircuit. For example, in a hard disk drive (HDD), one or more voltageregulators may be integrated into a motor controller, which may provideone or more regulated supplies to the motor controller and/or othercomponents or chips in the HDD (e.g., system-on-chip (SoC),preamplifiers, dynamic random access memory (DRAM) etc.).

FIG. 1 illustrates an exemplary on-chip voltage regulator 10, along withinternal field effect transistor (FET) drivers, included in anintegrated circuit chip 20. The voltage regulator 10 may be configuredto supply regulated voltage to load 76 through an inductor 72 and/or acapacitor 74. In various embodiments, a dotted line 14 in FIG. 1 mayindicate a boundary of the chip 20, and the load 76, inductor 72 and/orcapacitor 74 may be external to the integrated circuit chip 20. It willbe apparent to those skilled in the art that although the voltageregulator 10 is illustrated to supply regulated voltage to componentsexternal to the chip 20, in various embodiments, the voltage regulator10 may also drive components internal to the chip 20 along with (orinstead of) driving the external load 76.

In various embodiments, the voltage regulator 10 may include a driver28, which may further include a high side driver 32 and a P-channel FET(PFET) driver 34. The high side driver 32 may be configured to drive thePFET driver 34, and hence, for illustrative purposes, the high sidedriver 32 and the PFET driver 34 have been illustrated as a single unit.It will be apparent to those skilled in the art that unlike theillustration of FIG. 1, the high side driver 32 and the PFET driver 34need not be physically combined. In various embodiments, the driver 28may also include a low side driver 36 configured to drive an N-channelFET (NFET) driver 38, also included in the driver 28.

In various embodiments, the voltage regulator 10 may also include acontroller 24, which may be configured to control the operations of thedriver 28, including the high side driver 32 and the low side driver 36.The controller 24 may receive a reference voltage Vref, and the voltageregulator 10 may be configured to regulate its output voltage to make itsubstantially equal to k*Vref, where Vref is the reference voltage and kmay be a programmable constant.

In various embodiments, the integrated circuit chip 20 may also includea VDD pin 40, which may be configured to receive a supply voltage VDD(e.g., 5V); a ground pin GND 48, which may be coupled to a ground supplyGND; a feedback pin FB 52, which may be configured to receive a feedbackvoltage Vout supplied to the load 76 (or a voltage proportional to thefeedback voltage Vout, for example, M*Vout, where M is a programmableconstant); and an output voltage pin OUT 44, which may be configured tooutput the regulated voltage. In various embodiments, the supply voltageVDD may be coupled to the high side driver 32 and/or PFET driver 34, theground voltage GND may be coupled to the low side driver 36 and/or NFETdriver 38, and the feedback signal FB may be coupled to the controller24. The output of the high side driver 32 and/or PFET driver 34 and theoutput of the low side driver 36 and/or NFET driver 38 may be coupled tothe output pin OUT 44.

In various embodiments, the high side driver 32 may control theswitching of the PFET driver 34 such that the PFET driver 34 drives theoutput pin OUT 44 towards the supply voltage VDD 40. On the other hand,the low side driver 36 may control the switching of the NFET driver 38such that the NFET driver 38 pulls the output pin OUT 44 towards theground supply GND. By appropriately controlling the switching of thePFET and the NFET drivers using the controller 24, the output voltage atOUT 44 may be controlled. Exemplary internal structures of the FETdrivers and/or the high end and low end drivers are well known to thoseskilled in the art, and hence, a more detailed discussion is omittedherein. The controller 24 may receive feedback voltage Vout 78 throughthe feedback pin FB 52, and regulate the switching of the PFET and theNFET drivers such that Vout is substantially equal to the referencevoltage Vref. In various embodiments, Vout may be proportional to thereference voltage Vref, i.e., Vout may be substantially equal to N*Vref,where N is a programmable constant.

In various embodiments, the on-chip regulator 10 may act as a downconvertor, by generating output voltage (e.g., 1.2V or 2.5V) less thanor equal to the supply voltage VDD (e.g., 5V). In various embodiments,the voltage regulator 10 may be utilized in a plurality of electronicsystems. For example, in a hard disk drive (HDD), a motor controller mayintegrate one or more voltage regulators to provide regulated powersupply to the motor controller and/or other components external to themotor controller (e.g., system-on-chip (SoC), preamplifiers, dynamicrandom access memory (DRAM) etc.).

The voltage regulator 10 may be suitable for numerous low powerapplications, where the power requirement of the load 76 is relativelylow. But as the power requirement of the load 76 increases, the FETdrivers (i.e., the PFET driver 34 and the NFET driver 38) may be neededto control relatively large current components. However, because oflimited power and/or heat dissipation capabilities and/or limitedcurrent carrying capabilities of the FET drivers and/or chip 20, it maynot always be possible to have on-chip FET drivers for high powerapplications. In these types of applications, in various embodiments, itmay be possible to have external FET drivers, while other components ofthe regulator and the controller may still be inside an integratedcircuit chip.

FIG. 2 illustrates another exemplary on-chip voltage regulator 100,included in an integrated circuit chip 120 and configured to be coupledto one or more external FET drivers. Similar to the voltage regulator 10of FIG. 1, the voltage regulator 100 of FIG. 2 may be configured tosupply regulated voltage to load 176, inductor 172 and/or capacitor 174,and may include a driver 128. The driver 128 may include a high sidedriver 132 and a low side driver 136.

However, unlike the voltage regulator 10 of FIG. 1, the voltageregulator 100 of FIG. 2 may not include any internal FET drivers (i.e.,PFET drivers and/or NFET drivers). Instead, the voltage regulator 100may be coupled to external FET drivers (high side PFET 134E and low sideNFET 138E) that may be external to the voltage regulator and/or externalto the chip 120. Thus, in various embodiments, the external FET driversmay be a part of the load 176, be a part of one or more externalcomponents (that is external to the chip 120), and/or may be stand aloneFET drivers external to the chip 120. The high side driver 132 maycontrol the switching of the external high side PFET 134E through a highgate pin HG 154, and the low side driver 136 may control the switchingof the external low side NFET 138E through a low gate pin LG 156.

In various embodiments, the operation of the voltage regulator 100 maybe similar to the voltage regulator 10 of FIG. 1. For example, the highside driver 132 may control the switching of the external PFET driver134E (through pin HG 154) such that the PFET driver 34 drives the outputpin OUT 144 towards the supply voltage 140. On the other hand, the lowside driver 136 may control the switching of the external NFET driver138E such that the NFET driver 138E pulls the output pin OUT 144 towardsthe ground supply GND. By appropriately controlling the switching of theexternal FET drivers using controller 124, the output voltage at OUT 144may be controlled. The controller 124 may also receive feedback voltageVout 178 through the feedback pin FB 152, and regulate the switching ofthe external PFET and the NFET drivers such that Vout is substantiallyequal to the reference voltage Vref.

The external FET drivers of FIG. 2 may have more power and/or heatdissipation capabilities and/or more current carrying capabilities ascompared to the internal FET drivers of FIG. 1. Accordingly, in variousembodiments, the voltage regulator 100 of FIG. 2 may be used forapplications where there is a relatively higher power/load requirement.For example, the voltage regulator 100 may be used in high performance2.5″ mobile HDD, desktop 3.5″ drives, enterprise drives, etc. In theseapplications, the regulator control may be integrated within a chip,whereas the FET drivers may be external to the chip.

Thus, FIG. 1 illustrates an on-chip voltage regulator 10 with internalFET drivers, whereas FIG. 2 illustrates another on-chip voltageregulator 100 where the FET drivers are not part of the chip. Aspreviously discussed, the voltage regulator 10 may be suitable forrelatively low power applications, whereas the voltage regulator 100 maybe suitable for high power applications.

However, an IC chip may be used for a number of applications, withvarying requirements of regulatory output capabilities. Moreover, thechip 20 of FIG. 1 (including the regulator 10) may not be used withexternal FET drivers. Similarly, the chip 120 of FIG. 2 (including theregulator 100) may not be used with external components that lackexternal FET drivers. Thus, it may be necessary to maintain two sets ofIC chips: one with internal FET drivers (like FIG. 1) and the otherwithout internal FET drivers (like FIG. 2), and only one of the two setsof chips may be used for a particular application, based on aconfiguration of external components (e.g., based on a presence or anabsence of external FET drivers in the external components), in additionto being based on the power requirement of the load and/or the externalcomponents.

SUMMARY

In various embodiments, the present invention provides an apparatus anda method for self configuring voltage regulators. More specifically,there is provided, in accordance with various embodiments of the presentinvention, a voltage regulator comprising a first driver, a seconddriver, and a controller configured to control the first driver and thesecond driver to selectably operate in one of a plurality of operatingmodes, including an external driver mode and an internal driver mode,wherein which one of the plurality of operating modes is selected may bebased on presence or absence of one or more external drivers. In variousembodiments, wherein the voltage regulator may be included in a firstcomponent, and wherein the controller may be configured to detect aconfiguration of one or more external components coupled to the firstcomponent and is further configured to operate either in said externaldriver mode or in said internal driver mode responsive at least in partto said detection. The voltage regulator may be configured to detect apresence or absence of the one or more external drivers in the one ormore external components. The controller may be configured to operate insaid external driver mode responsive at least in part to detecting apresence of one or more external drivers in the one or more externalcomponents, and wherein the controller may be further configured tooperate in said internal driver mode responsive at least in part todetecting an absence of an external driver in the one or more externalcomponents. The one or more external drivers that the voltage regulatoris configured to detect may be external field effect transistor (FET)drivers. The first driver may be configured to output a first outputvoltage and the second driver may be configured to output a secondoutput voltage, and the controller may be configured to control thefirst driver and the second driver such that the first output voltageand the second output voltage is substantially similar while theinternal driver mode is engaged.

In various embodiments, the first driver may be configured to output thefirst output voltage to a first output pin and the second driver may beconfigured to output the second output voltage to a second output pin,and the first output pin may be coupled to the second output pin whilethe internal driver mode is engaged. The first output pin and the secondoutput pin may be coupled to a third output pin while the internaldriver mode is engaged, and the third output pin may be coupled to thecontroller and configured to supply a regulated output voltage to a loadcoupled to the third output pin. The first driver may include a firsthigh side driver, a first p-channel field effect transistor (PFET)driver, a first low side driver, and a first n-channel field effecttransistor (NFET) driver, and the second driver may include a secondhigh side driver, a second PFET driver, a second low side driver, and asecond NFET driver. The first high side driver may be configured todrive the first PFET driver, the second high side driver may beconfigured to drive the second PFET driver, the first low side drivermay be configured to drive the first NFET driver and the second low sidedriver may be configured to drive the second NFET driver. The firstdriver may be configured to drive an external PFET driver and the seconddriver may be configured to drive an external NFET driver while theexternal driver mode is engaged. The first driver may be configured todrive the external PFET driver through a first output pin and the seconddriver may be configured to drive the external NFET driver through asecond output pin. A third output pin of the voltage regulator may becoupled to the external PFET driver and the external NFET driver, andthe third output pin may be coupled to the controller and configured tosupply a regulated output voltage to a load.

In various embodiments, the voltage regulator may be included in a firstcomponent, and the controller may be configured to receive an outputvoltage as feedback from one or more external components coupled to thefirst component, to receive a reference voltage, and to control thefirst driver and the second driver such that the received output voltageis substantially equal to the reference voltage. The first component maybe an integrated circuit chip.

There is also provided, in accordance with various embodiments of thepresent invention, a method for operating a voltage regulator includedin an integrated circuit chip, the method comprising detecting apresence or an absence of one or more external drivers in one or moreexternal components coupled to the integrated circuit chip, selectingone of an internal driver mode or an external driver mode responsive atleast in part to said detection, and operating the voltage regulator inthe selected one of the internal driver mode or the external drivermode. Said detecting the presence or absence of one or more externaldrivers may further comprise disabling a first driver included in thevoltage regulator, driving a second driver such that an output of thesecond driver is low, measuring an output of the voltage regulator, anddetermining the presence or absence of one or more external driversresponsive at least in part to said measured output. In variousembodiments, said detecting the presence or absence of one or moreexternal drivers may further comprise determining that one or moreexternal drivers are absent if the measured output of the voltageregulator is low, and determining that one or more external drivers arepresent if the measured output of the voltage regulator is high. Themethod may further comprise confirming said detection of presence orabsence of the one or more external drivers, and confirming properoperation of a first driver and a second driver included in the voltageregulator. Said selecting the internal driver mode or the externaldriver mode may further comprise selecting the external drive mode if apresence of the one or more external drivers is detected, and selectingthe internal driver mode if an absence of the one or more externaldrivers is detected.

In various embodiments, said operating the voltage regulator may furthercomprise operating, if the internal driver mode is selected, a firstdriver and a second driver included in the voltage regulator such thatan output voltage of the first driver is substantially equal to anoutput voltage of the second driver, said operating the first driver andthe second driver may further comprise driving a first p-channel fieldeffect transistor (PFET) driver using a first high side driver, anddriving a first n-channel field effect transistor (NFET) driver using afirst low side driver. Said operating the first driver and the seconddriver may further comprise combining an output of the first PFET driverand the first NFET driver to produce the output voltage of the firstdriver, wherein the first high side driver, the first low side driver,the first PFET driver and the first NFET driver are included in thefirst driver. Said operating the first driver and the second driver mayfurther comprise driving a second PFET driver using a second high sidedriver, driving a second NFET driver using a second low side driver, andcombining an output of the second PFET driver and the second NFET driverto produce the output voltage of the second driver, wherein the secondhigh side driver, the second low side driver, the second PFET driver andthe second NFET driver are included in the second driver. Said operatingthe voltage regulator may further comprise operating, if the externaldriver mode is selected, a first driver and a second driver included inthe voltage regulator such that an output voltage of the first drivercontrols an external p-channel field effect transistor (PFET) driver andan output voltage of the second driver controls an external n-channelfield effect transistor (NFET) driver. The one or more external driversthat are to be detected may be external field effect transistor (FET)drivers.

There is also provided, in accordance with various embodiments of thepresent invention, a method comprising coupling a voltage regulator,included in a first component, to one or more external components,wherein the one or more external components are external to the firstcomponent, the external components including one or more loads to bedriven by an output of the voltage regulator, selecting one of aninternal driver mode or an external driver mode based at least in parton a configuration of the one or more external components, and operatingthe voltage regulator in the selected one of the internal driver mode orthe external driver mode to supply a regulated voltage to the one ormore loads. The method may further comprise detecting the configurationof the one or more external components by determining whether one ormore external field effect transistor (FET) drivers are present in theone or more external components. Said selecting the internal driver modeor the external driver mode may further comprise selecting the externaldriver mode if one or more external FET drivers are present in the oneor more external components, and selecting the internal driver mode ifone or more external FET drivers are absent in the one or more externalcomponents.

In various embodiments, said operating the voltage regulator may furthercomprise operating, if the internal driver mode is selected, a firstdriver and a second driver included in the voltage regulator such thatan output voltage of the first driver is substantially equal to anoutput voltage of the second driver. Said operating the voltageregulator may further comprise operating, if the external driver mode isselected, a first driver and a second driver included in the voltageregulator such that an output voltage of the first driver controls anexternal p-channel field effect transistor (PFET) driver and an outputvoltage of the second driver controls an external n-channel field effecttransistor (NFET) driver, wherein the external PFET driver and theexternal NFET driver may be included in the configuration of the one ormore external components. In various embodiments, said first componentmay be an integrated circuit chip.

BRIEF DESCRIPTION OF THE DRAWINGS

Embodiments of the present invention will be readily understood by thefollowing detailed description in conjunction with the accompanyingdrawings. To facilitate this description, like reference numeralsdesignate like structural elements. Embodiments of the invention areillustrated by way of example and not by way of limitation in thefigures of the accompanying drawings.

FIG. 1 illustrates an exemplary on-chip voltage regulator, along withinternal field effect transistor (FET) drivers, included in anintegrated circuit chip;

FIG. 2 illustrates another exemplary on-chip voltage regulator, includedin an integrated circuit chip and configured to be coupled to one ormore external FET drivers;

FIG. 3 illustrates an exemplary on-chip voltage regulator, included inan integrated circuit chip, in accordance with various embodiments ofthe present invention;

FIG. 4 illustrates the on-chip voltage regulator of FIG. 3 coupled toexternal components that lack any external FET driver, in accordancewith various embodiments of the present invention;

FIG. 5 illustrates the on-chip voltage regulator of FIG. 3 coupled toexternal components that include external FET drivers, in accordancewith various embodiments of the present invention;

FIG. 6 illustrates an exemplary flow diagram for a method for detectinga presence (or absence) of external FET drivers, in accordance withvarious embodiments of the present invention; and

FIG. 7 is a block diagram of an exemplary system suitable for use topractice the present invention, in accordance with various embodiments.

DETAILED DESCRIPTION OF EMBODIMENTS OF THE INVENTION

In the following detailed description, reference is made to theaccompanying drawings which form a part hereof wherein like numeralsdesignate like parts throughout, and in which is shown by way ofillustration embodiments in which the invention may be practiced. It isto be understood that other embodiments may be utilized and structuralor logical changes may be made without departing from the scope of thepresent invention. Therefore, the following detailed description is notto be taken in a limiting sense, and the scope of embodiments inaccordance with the present invention is defined by the appended claimsand their equivalents.

Various operations may be described as multiple discrete operations inturn, in a manner that may be helpful in understanding embodiments ofthe present invention; however, the order of description should not beconstrued to imply that these operations are order dependent.

The description may use the phrases “in an embodiment,” or “inembodiments,” which may each refer to one or more of the same ordifferent embodiments. Furthermore, the terms “comprising,” “including,”“having,” and the like, as used with respect to embodiments of thepresent invention, are synonymous.

FIG. 3 illustrates an exemplary on-chip voltage regulator 200, includedin an integrated circuit chip 220, in accordance with variousembodiments of the present invention. The voltage regulator 200 mayinclude two drivers: driver 228 a and driver 228 b. In variousembodiments, each of the drivers 228 a and 228 b may include a high sidedriver, a high side PFET driver, a low side driver, and a low side NFETdriver, as illustrated in FIG. 3. Thus, each of the drivers 228 a and228 b may have some similarity with the driver 28 of FIG. 1.

In various embodiments, the high side drivers 232 a and 232 b and/or thePFET drivers 234 a and 234 b may be coupled to a supply voltage (e.g.,5V) pin VDD 240, while the low side drivers 236 a and 236 b and/or theNFET drivers 238 a and 238 b may be coupled to a ground pin GND 248. Theoutput of the driver 228 a may be coupled to a low gate pin LG 256,whereas the output of the driver 228 b may be coupled to a high gate pinHG 254. The regulator 200 may also include a controller 224, which maybe configured to control the operations of the drivers 228 a and 228 b,including the respective high side drivers 232 a and 232 b and/or thelow side driver 236 a and 236 b. The controller 224 may be configured todrive the LG 256 and the HG 254 pin independently, through driver 228 aand driver 228 b, respectively. That is, the two drivers 228 a anddriver 228 b may work independently to control the outputs of the pinsLG 256 and HG 254.

In various embodiments, the voltage regulator 200 may be configured todetect the presence or absence of external FET drivers in one or moreexternal components to which the chip 220 may be coupled, as will befurther discussed in more detail herein. Additionally, based at least inpart on the detection, the voltage regulator 200 may be configured sothat it may operate either with external components that lack externalFET drivers or with external components that include external FETdrivers. That is, the voltage regulator 200 may be configured to operatewith external components irrespective of the presence or absence ofexternal FET drivers in the external components, as will be furtherdiscussed in detail herein.

FIG. 4 illustrates the on-chip voltage regulator 200 of FIG. 3 coupledto one or more external components 370 that lack any external FETdriver, in accordance with various embodiments of the present invention.As the voltage regulator 200 in FIG. 4 is configured to operate withexternal components 370 that lack any external FET drivers, the voltageregulator 200 in FIG. 4 may be configured to utilize its internal FETdrivers to regulate the output power supply. Thus, the mode of operationof the voltage regulator 200 in FIG. 4 may also be referred to asinternal driver mode.

Referring again to FIG. 4, the LG 256, HG 254 and the OUT 244 pins maybe shorted and coupled to a load 376 through inductor 372 and/orcapacitor 374. As previously discussed, the controller 224 may beconfigured to drive the LG 256 and the HG 254 pin independently, throughdriver 228 a and driver 228 b, respectively. In the embodiments of FIG.4, the driver 228 a and driver 228 b are driven in identical manner,such that both the drivers output identical voltage at respective pinsLG 256 and the HG 254. Note that as will be readily understood bysomeone skilled in the art based on the disclosure and teachingsprovided herein, in various embodiments, the operating principles ofeach of the drivers 228 a and 228 b of FIG. 4 may be substantiallysimilar to the operating principles of the driver 28 of FIG. 1. Asdrivers 228 a and 228 b are driven identically by the controller 224,the drivers 228 a and 228 b operate in tandem (in a parallelconfiguration), and the voltage regulator 200 may provide an output(e.g., 1.2V or 2.5V) with almost double the driving strength as comparedto the voltage regulator 10 of FIG. 1.

FIG. 5 illustrates the on-chip voltage regulator 200 of FIG. 3 coupledto one or more external components 470 that include external FETdrivers, in accordance with various embodiments of the presentinvention. As the voltage regulator 200 in FIG. 5 is configured tooperate with external FET drivers, the mode of operation of the voltageregulator 200 of FIG. 5 may also be referred to as external driver mode.

Referring again to FIG. 5, the external components 470 may include anexternal high side PFET driver 234E and an external low side NFET drive238E. In various embodiments, the external PFET drive 234E may becoupled to the supply voltage VDD 240. On the other hand, the externalNFET drive 238E may be coupled to the ground GND 248.

In various embodiments, as previously discussed, the driver 228 b(including high and low side drivers 232 b and 236 b and/or the FETdrivers 234 b and 238 b) may be configured to control the high gate pinHG 254, which may in turn control the switching of the external PFET234E. The driver 228 b may be configured to control the switching of theexternal PFET 234E such that the PFET 234E drives the output pin OUT 244towards the supply voltage VDD 40. For example, in various embodiments,when driver 228 b drives the pin HG 254 to low (e.g., equal to ground,1.2V, or any other appropriate level of low voltage), the external PFETdriver 234E may be turned ON, resulting in driving the output pin OUT244 to a high voltage level (e.g., VDD).

On the other hand, as previously discussed, the driver 228 a (includinghigh and low side drivers 232 a and 236 a and/or the FET drivers 234 aand 238 a) may be configured to control the low gate pin LG 256, whichmay in turn control the switching of the external NFET 238E. The driver228 a may be configured to control the switching of the external NFET238E such that the NFET 238E drives the output pin OUT 244 towardsground GND 248. For example, in various embodiments, when driver 228 adrives the pin LG 256 to a high voltage (e.g., 2.5V, 5V, supply voltageVDD, or any other appropriate level of high voltage), the external NFETdriver 238E may be turned ON and may drive the output pin OUT 244towards ground GND 248

The controller 224 may control the operations of the external FETdrivers 234E and 238E through respective drivers 228 a and 228 b, basedat least in part on a reference voltage Vref and a feedback voltage Voutthrough the feedback pin FB 252. By appropriately controlling theswitching of the external FET drivers 234E and 238E, the output voltage(e.g., 1.2V or 2.5V) at OUT 244 may be regulated such that a differencebetween the load voltage Vout and the reference voltage level Vref isminimized.

As seen from FIGS. 4 and 5, the voltage regulator 200 may operate eitherin the internal driver mode (FIG. 4) or in the external driver mode(FIG. 5), based at least in part on the configuration of the externalcomponents (i.e., presence or absence of external FET drivers in theexternal components) coupled to the chip 220. However, in order tooperate in a correct mode (i.e., external or internal driver mode), thevoltage regulator 200 may need to be aware of the configuration of theexternal components. Also, in various embodiments, as the voltageregulator may have to be powered before powering various othercomponents (e.g., components, including a microprocessor, to which powermay be supplied by the voltage regulator), it may not always be possibleto detect the configuration of the external components during or beforepowering the voltage regulator.

In various embodiments, the voltage regulator 200 may be able to detecta presence (or absence) of external FET drivers, and configure itselfaccordingly. For example, if external FET drivers are detected, thevoltage regulator 200 may configure itself to enter the external drivermode, as discussed with respect to FIG. 5. On the other hand, if anabsence of external FET drivers is detected, the voltage regulator 200may configure itself to enter the internal driver mode, as discussedwith respect to FIG. 4.

FIG. 6 illustrates an exemplary flow diagram for a method 600 fordetecting a presence (or absence) of external FET drivers, in accordancewith various embodiments of the present invention. The method 600 mayalso be used to confirm that both the drivers 228 a and 228 b of thevoltage regulator 200 are operating as intended, without any failure.The method 600 may be applicable to the voltage regulator 200 of FIGS.3-5.

Referring to FIG. 6, initially, any one of the two drivers 228 a and 228b of the voltage regulator 200 may be disabled, and the other one of thetwo drivers may be driven such that its output is either high or low.For example, in various embodiments, at 610, driver 228 a may bedisabled, and driver 228 b may be driven such that HG 254 is low (e.g.,ground voltage, 1.2V or any other appropriate low voltage level).

At 614, the voltage level of the OUT 244 pin may be detected. Asillustrated in FIG. 4, if no external components are present, the OUT244 and the HG 254 pin would be shorted by the external components.Accordingly, in the internal driver mode, if the voltage of HG 254 pinis low, the voltage of OUT 244 pin will also be low. On the other hand,as illustrated in FIG. 5 and as previously discussed, if external FETdrivers are present and if the pin HG 254 is low, the external PFETdriver 234E may be turned ON, resulting in driving the output pin OUT244 at a high voltage level (e.g., 2.5V, 5V, supply voltage or any otherappropriate level of high voltage).

Accordingly, at 616, if the OUT 244 is low, it may be determined, at620, that external FET drivers have not been detected (i.e., absence ofexternal FET drivers detected). On the other hand, if the OUT 244 ishigh, it may be determined, at 660, that external FET drivers arepresent.

Once the presence or absence of external FET drivers is detected, it maybe intended to confirm the detection and/or confirm that both thedrivers 228 a and 228 b are working properly. All or part of theremaining portion of the method 600 may be directed towards confirmingthe detection and/or confirming proper functioning of both the drivers228 a and 228 b.

Referring again to FIG. 6, if presence of external FET drivers is notdetected at 620, the driver 228 b may be disabled at 624, and the driver228 a may be driven such that LG 256 pin is high. At 628, the voltagelevel at OUT 244 may be detected. The OUT 244 may be high (i.e., Yes at632) if external FET drivers are not present and if both drivers 228 aand 228 b are properly functioning, because in that case, OUT pin 244may follow the LG 244 pin as these two pins are shorted (see FIG. 4).Thus, at 636, the absence of external drivers and/or proper functioningof the drivers 228 a and 228 b may be confirmed, subsequent to which thevoltage regulator 200 may operate according to the internal driver modeat 644, as has been previously discussed with respect to FIG. 4. If theOUT 244 is not high at 632 (i.e., No at 632), it may be an indication ofmalfunctioning of the driver 228 a and/or driver 228 b (or any otherproblem in the voltage regulator 200, the integrated circuit chip 220,and/or external components to which the chip 220 is coupled).

On the other hand, if presence of external FET drivers is detected at660, at 664 driver 228 b may be disabled and driver 228 a may be drivensuch that the voltage of the pin LG 256 is high. As previously discussedwith respect to FIG. 5, in the presence of external FET drivers, if LG256 is high, the external NFET driver 238E may be turned ON and maydrive the output pin OUT 244 towards low voltage (i.e., ground GND 248).Accordingly, if the OUT 244 is low at 672 (i.e., Yes at 672), thepresence of external FET drivers may be confirmed, along withconfirmation of proper functioning of both drivers 228 a and 228 b,subsequent to which the voltage regulator 200 may operate according tothe external driver mode at 684, as has been discussed with respect toFIG. 5. On the other hand, if the OUT 244 is not low at 672 (i.e., No at672), it may be an indication of malfunctioning of the driver 228 aand/or driver 228 b (or any other problem in the voltage regulator 200,the integrated circuit chip 220, and/or external components to which thechip 220 is coupled).

As will be apparent to those skilled in the art, selection of the driverfor disablement at 610 is purely exemplary in nature. Additionally,selection of the voltage level during various operations of method 600is also purely exemplary in nature. For example, at 610, HG 254 couldhave been driven to a high voltage (instead of a low voltage),accompanied by corresponding changes in other operations of method 600,as will be readily understood by those skilled in the art based on thedisclosure and teachings provided herein.

The voltage regulator 200 of FIGS. 3-5 has several advantages over theprior art voltage regulators 10 and 100 of FIGS. 1 and 2, respectively.Unlike the prior art voltage regulators 10 or 100, the voltage regulator200 may operate with external components irrespective of whether theexternal components include or lack external FET drivers. Thus, thevoltage regulator 200 may be configured to be coupled to a load that hasa relatively low power requirement (which usually lacks external FETdrivers) or to a load that has a relatively high power requirement(which usually includes external FET drivers).

FIG. 7 is a block diagram of an exemplary system suitable for use topractice the present invention, in accordance with various embodiments.As illustrated, system 700 includes one or more processors or processorcores 702, and system memory 704. For the purpose of this application,including the claims, the terms “processor” and “processor cores” may beconsidered synonymous, unless the context clearly requires otherwise.Additionally, system 700 includes mass storage devices 706 (such asdiskette, hard drive, compact disc read only memory (CDROM) and soforth), input/output devices 708 and communication interfaces 710 (suchas network interface cards, modems and so forth). The elements of FIG. 7may be coupled to each other via system bus 712, which represents one ormore buses. In the case of multiple buses, they may be bridged by one ormore bus bridges (not illustrated).

Each of these elements performs its conventional functions known in theart. In particular, system memory 704 and mass storage 706 may beemployed to store a working copy and a permanent copy of the programminginstructions implementing all or a portion of earlier describedfunctions, herein collectively denoted as 722. The instructions 722 maybe assembler instructions supported by processor(s) 702 or instructionsthat can be compiled from high level languages, such as C.

The permanent copy of the programming instructions may be placed intopermanent storage 706 in the factory, or in the field, through, forexample, a distribution medium (not shown), such as a compact disc (CD),or through communication interface 710 (from a distribution server (notshown)). That is, one or more distribution media having instructions 722may be employed to distribute the instructions 722 and program variouscomputing devices. The constitution of these elements 702-712 aregenerally well known, and accordingly will not be further described.

In various embodiments, the system 700 may include one or moreintegrated circuit chips, with one or more integrated voltage regulator,such as the voltage regulator 200 of FIGS. 3-5. For example, in the massstorage device 706, there may be included a hard disk drive (HDD),including a motor controller that may integrate one or more voltageregulators (e.g., voltage regulator 200 of FIGS. 3-5) to provideregulated power supply to the motor controller and/or other componentsexternal to the motor controller (e.g., processor 702, system-on-chip(SoC), preamplifiers, dynamic random access memory (DRAM), or any othercomponents of system 700). In various embodiments, the voltage regulatormay also be used in high performance 2.5″ mobile HDD, desktop 3.5″drives, enterprise drives, etc. In various embodiments, the voltageregulator may be configured to operate either in an internal driver modeor an external driver mode, based at least in part of a configuration ofexternal components coupled to the voltage regulator. The programminginstructions stored in logic 722 and/or the processor 702 may beconfigured to control one or more operations of the voltage regulator.

Although specific embodiments have been illustrated and describedherein, it will be appreciated by those of ordinary skill in the art andothers, that a wide variety of alternate and/or equivalentimplementations may be substituted for the specific embodiment shown anddescribed without departing from the scope of the present invention.This disclosure covers all methods, apparatus, and articles ofmanufacture fairly falling within the scope of the appended claimseither literally or under the doctrine of equivalents. For example,although the above discloses example systems including, among othercomponents, software or firmware executed on hardware, it should benoted that such systems are merely illustrative and should not beconsidered as limiting. In particular, it is contemplated that any orall of the disclosed hardware, software, and/or firmware componentscould be embodied exclusively in hardware, exclusively in software,exclusively in firmware or in some combination of hardware, software,and/or firmware. This application is intended to cover any adaptationsor variations of the embodiment discussed herein. Therefore, it ismanifested and intended that the invention be limited only by the claimsand the equivalents thereof.

1. A voltage regulator comprising: a first driver; a second driver; anda controller configured to control the first driver and the seconddriver to selectably operate in one of a plurality of operating modes,including an external driver mode and an internal driver mode, whereinwhich one of the plurality of operating modes is selected is based onpresence or absence of one or more external drivers.
 2. The voltageregulator of claim 1, wherein the voltage regulator is included in afirst component; and wherein the controller is configured to detect aconfiguration of one or more external components coupled to the firstcomponent and is further configured to operate either in said externaldriver mode or in said internal driver mode responsive at least in partto said detection.
 3. The voltage regulator of claim 2, wherein thevoltage regulator is configured to detect a presence or absence of theone or more external drivers in the one or more external components. 4.The voltage regulator of claim 3, wherein the one or more externaldrivers that the voltage regulator is configured to detect are externalfield effect transistor (FET) drivers.
 5. The voltage regulator of claim2, wherein the controller is configured to operate in said externaldriver mode responsive at least in part to detecting a presence of oneor more external drivers in the one or more external components; andwherein the controller is configured to operate in said internal drivermode responsive at least in part to detecting an absence of an externaldriver in the one or more external components.
 6. The voltage regulatorof claim 2, wherein the first component is an integrated circuit chip.7. The voltage regulator of claim 1, wherein the first driver isconfigured to output a first output voltage and the second driver isconfigured to output a second output voltage; and wherein the controlleris configured to control the first driver and the second driver suchthat the first output voltage and the second output voltage issubstantially similar while the internal driver mode is engaged.
 8. Thevoltage regulator of claim 7, wherein the first driver is configured tooutput the first output voltage to a first output pin and the seconddriver is configured to output the second output voltage to a secondoutput pin; and wherein the first output pin is coupled to the secondoutput pin while the internal driver mode is engaged.
 9. The voltageregulator of claim 8, wherein the first output pin and the second outputpin is coupled to a third output pin while the internal driver mode isengaged; and wherein the third output pin is coupled to the controllerand is configured to supply a regulated output voltage to a load coupledto the third output pin.
 10. The voltage regulator of claim 1, whereinthe first driver includes a first high side driver, a first p-channelfield effect transistor (PFET) driver, a first low side driver, and afirst n-channel field effect transistor (NFET) driver; and wherein thesecond driver includes a second high side driver, a second PFET driver,a second low side driver, and a second NFET driver.
 11. The voltageregulator of claim 10, wherein the first high side driver is configuredto drive the first PFET driver, the second high side driver isconfigured to drive the second PFET driver, the first low side driver isconfigured to drive the first NFET driver and the second low side driveris configured to drive the second NFET driver.
 12. The voltage regulatorof claim 1, wherein the first driver is configured to drive an externalPFET driver and the second driver is configured to drive an externalNFET driver while the external driver mode is engaged.
 13. The voltageregulator of claim 12, wherein the first driver is configured to drivethe external PFET driver through a first output pin and the seconddriver is configured to drive the external NFET driver through a secondoutput pin; wherein a third output pin of the voltage regulator iscoupled to the external PFET driver and the external NFET driver; andwherein the third output pin is coupled to the controller and isconfigured to supply a regulated output voltage to a load.
 14. Thevoltage regulator of claim 1, wherein the voltage regulator is includedin a first component; and wherein the controller is configured toreceive an output voltage as feedback from one or more externalcomponents coupled to the first component, to receive a referencevoltage, and to control the first driver and the second driver such thatthe received output voltage is substantially equal to the referencevoltage.
 15. A method for operating a voltage regulator included in anintegrated circuit chip, the method comprising: detecting a presence oran absence of one or more external drivers in one or more externalcomponents coupled to the integrated circuit chip; selecting one of aninternal driver mode or an external driver mode responsive at least inpart to said detection; and operating the voltage regulator in theselected one of the internal driver mode or the external driver mode;wherein said detecting the presence or absence of one or more externaldrivers further comprises disabling a first driver included in thevoltage regulator, driving a second driver included in the voltageregulator, such that an output of the second driver is low, measuring anoutput of the voltage regulator, determining the presence or absence ofone or more external drivers responsive at least in part to saidmeasured output, determining that one or more external drivers areabsent if the measured output of the voltage regulator is low, anddetermining that one or more external drivers are present if themeasured output of the voltage regulator is high.
 16. The method ofclaim 15, wherein said operating the voltage regulator furthercomprises: operating, if the internal driver mode is selected, the firstdriver and the second driver such that an output voltage of the firstdriver is substantially equal to an output voltage of the second driver.17. The method of claim 16, wherein said operating the first driver andthe second driver further comprises: driving a first p-channel fieldeffect transistor (PFET) driver using a first high side driver; anddriving a first n-channel field effect transistor (NFET) driver using afirst low side driver.
 18. The method of claim 17, wherein saidoperating the first driver and the second driver further comprises:combining an output of the first PFET driver and the first NFET driverto produce the output voltage of the first driver, wherein the firsthigh side driver, the first low side driver, the first PFET driver andthe first NFET driver are included in the first driver.
 19. The methodof claim 16, wherein said operating the first driver and the seconddriver further comprises: driving a second PFET driver using a secondhigh side driver; driving a second NFET driver using a second low sidedriver; and combining an output of the second PFET driver and the secondNFET driver to produce the output voltage of the second driver, whereinthe second high side driver, the second low side driver, the second PFETdriver and the second NFET driver are included in the second driver. 20.The method of claim 15, further comprising: confirming said detection ofpresence or absence of the one or more external drivers; and confirmingproper operation of the first driver and the second driver included inthe voltage regulator.
 21. The method of claim 15, wherein saidselecting the internal driver mode or the external driver mode furthercomprises: selecting the external drive mode if a presence of the one ormore external drivers is detected; and selecting the internal drivermode if an absence of the one or more external drivers is detected. 22.A method for operating a voltage regulator included in an integratedcircuit chip, the method comprising: detecting a presence or an absenceof one or more external drivers in one or more external componentscoupled to the integrated circuit chip; selecting one of an internaldriver mode or an external driver mode responsive at least in part tosaid detection; operating the voltage regulator in the selected one ofthe internal driver mode or the external driver mode; operating, if theexternal driver mode is selected, a first driver and a second driverincluded in the voltage regulator such that an output voltage of thefirst driver controls an external p-channel field effect transistor(PFET) driver and an output voltage of the second driver controls anexternal n-channel field effect transistor (NFET) driver.
 23. The methodof claim 22, wherein the one or more external drivers that are to bedetected are external field effect transistor (FET) drivers.
 24. Amethod comprising: coupling a voltage regulator, included in a firstcomponent, to one or more external components, wherein the one or moreexternal components are external to the first component, the externalcomponents including one or more loads to be driven by an output of thevoltage regulator; selecting one of an internal driver mode or anexternal driver mode based at least in part on a configuration of theone or more external components; and operating the voltage regulator inthe selected one of the internal driver mode or the external driver modeto supply a regulated voltage to the one or more loads; wherein saidoperating the voltage regulator further comprises operating, if theexternal driver mode is selected, a first driver and a second driverincluded in the voltage regulator such that an output voltage of thefirst driver controls an external p-channel field effect transistor(PFET) driver and an output voltage of the second driver controls anexternal n-channel field effect transistor (NFET) driver, wherein theexternal PFET driver and the external NFET driver are included in theone or more external components.
 25. The method of claim 24, furthercomprising: detecting the configuration of the one or more externalcomponents by determining whether one or more external field effecttransistor (FET) drivers are present in the one or more externalcomponents.
 26. The method of claim 24, wherein said selecting theinternal driver mode or the external driver mode further comprises:selecting the external driver mode if one or more external FET driversare present in the one or more external components; and selecting theinternal driver mode if one or more external FET drivers are absent inthe one or more external components.
 27. The method of claim 24, whereinsaid operating the voltage regulator further comprises: operating, ifthe internal driver mode is selected, the first driver and the seconddriver such that an output voltage of the first driver is substantiallyequal to an output voltage of the second driver.
 28. The method of claim24, wherein said first component is an integrated circuit chip.